Method of hulling pistachio nuts

ABSTRACT

A pistachio huller is provided wherein a means having projections pushes unhulled nuts between the surface of the means having projections and a surface of a means having slots, the slots being narrower than the pistachio nuts to be hulled. The projections protrude into the slots and the hulls are ruptured and abraded through contact between the surface of the means with projection and the surface of the strips forming the means having slots whereby the nuts are hulled.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to a huller for the removal of the hullcontaining a pistachio nut. My invention finds particular application asa pistachio huller. In particular my invention is directed to a methodand apparatus for a huller which ruptures and abrades the hullcontaining a pistachio nut.

2. Description of the Prior Art

The current methods and apparatuses in use for pistachio dehulling workadequately and are primarily wet process hullers using large volumes ofwater.

It is noted, in U.S. Pat. No. 4,304,665 by Jay J. McFarland and BertramE. Saunder for a "Pistachio Huller" that the pistachio industry hasgrown commercially in the San Joaquin Valley of the State of Californiaduring recent years with substantial acreage of this delicious nut beingplanted. These plantings are now in production and without the cheaplabor of foreign countries it is not economically feasible to hull theharvested pistachios by hand. Noted in that patent is the statement thatinsofar as they could determine, prior to their invention, there hadnever been a practical mechanical huller for pistachios. The McFarland,et al patent discloses a two stage huller, the first stage to rupturethe pericarps and to remove a portion of the hull and a second stage tostrip the remaining portion of the pericarp from the shells. This patentdiscusses one embodiment used in connection with water wherein a waternozzle provides water to moisten and soften the pericarp and to rinsethe fragments of pericarp from the shell. This type of prior art huller,in application, is water assisted. As in other prior art hullerssubstantial amounts of water are used. As will be described in greaterdetail hereinbelow, my invention is a method and apparatus for the dryhulling of pistachio nuts and is directed to overcome the necessity forthe use of water while hulling pistachio nuts and other associatedproblems of the prior art.

It was in the late 1960's and early 1970's that most of 31,000 acres ofpistachios were planted in the San Joaquin Valley of the State ofCalifornia, that 1977 saw the first crop of California's pistachios, andthat with little knowledge the questions then asked were: Now that wehave them what do we do with them? How do we process them? Moreimportantly, how do we hull them? My invention described hereinbelowanswers the latter questions.

Further, the hulling of pistachio nuts is known to present unusualproblems. The hulls must be promptly removed after harvest ordiscoloration to the pistachio shell will occur within 24 hours anddamage to the nut can result if the pistachio hull is not promptlyremoved after harvest. More commercial pistachio shells are dyed pink orred to hide this discoloration. The hull of the pistachio is strongerthan most nuts and has a greater adherence to the shell than most nutsand it is therefore more difficult to remove.

SUMMARY OF THE INVENTION

In accordance with the present invention, an apparatus is provided forremoving the hull containing a pistachio nut which comprises: a supportmeans; a means having slots attached to the suppot means; a means havingprojections disposed on a surface thereof with the projections beingspaced apart on the surface and the surface movably mounted on thesupport means with the surface having projections disposed in closeproximity to the surface of the means having slots so that theprojections extend into the slots; a means for moving the surface havingprojections coupled to the means having a plurality of projections so asto pass at least one of the projections into each of the slots; and ameans for dispensing pistachio nuts to be hulled in abrading engagementbetween the surface of the means having slots and the surface havingprojections.

The invention further comprising a method of removing a hull containinga pistachio nut the method comprising the steps of depositing anunhulled pistachio nut between a means having slots, the slots beingnarrower than the pistachio nuts, and a means having projectionsextending outward from a surface thereof, of passing the unhulledpistachio nut between the surface having projections and the surface ofthe means having slots by means of moving the surface of the meanshaving projections, so as to push the nut in said slots with theprojections, and of abrading the hull from the pistachio nut by means ofthe surface having projections and the surface of the means having slotscontacting the hull while the unhulled pistachio nut passes between thesurface having projections and the surface of the means having slots.

It is accordingly an object of the present invention to provide a hullercapable of dry processing of pistachios without breaking many of theshells or damaging the nuts.

Another object of the present invention is to provide a huller, thatonce adjusted, is operable despite the variation in size of thepistachio nuts being hulled and a huller that can handle all sizes ofpistachio nuts from the field run harvest.

Another object of the present invention is to provide a huller that iseasily portable and can be used at harvest in the orchard.

Another object of the present invention is to provide a huller that usesvery little power for the volume of product processed, is economical,efficient and effective for hulling the field run harvest of pistachionuts.

Another object of the present invention is to provide a huller whereinthe hulls after separation from the shells are available for animalfeed.

Another object of the present invention is to provide a huller whereinthe high quality flavor of the pistachio nut is not tainted bydisagreeable flavors as may result from the water separation processes.

Another object of the present invention is to provide a huller which isself-cleaning and has a roller and means with slots that are easilyreplaced or repaired.

Yet another object of the present invention is to provide a huller whichis easily adjustable to permit the huller to dehull pistachio nuts ofdifferent sizes during its normal operation.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings forming a part of the specification like referencenumerals are employed to designate like parts throughout the same.

FIG. 1 is a side elevation view of the huller of the preferredembodiment of the present invention.

FIG. 2 is a top planar view of the huller of the preferred embodiment ofthe present invention without the hopper, air separator, or shoot.

FIG. 3 is a perspective view of the huller shown in FIG. 1 and FIG. 2without the hopper, air separator or shoot.

FIG. 4 is a top perspective view of the means having slots and itssupporting structure employed in the preferred embodiment shown in FIGS.1, 2 and 3.

FIG. 5 is a bottom view of the means having slots and its supportingstructure employed in the embodiment shown in FIGS. 1, 2 and 3.

FIG. 6 is a fragmentary view of the cylinder and means having slots ofthe embodiment shown in FIGS. 1, 2 and 3.

FIG. 7 is a cross section of the drum and a fragmentary section of themeans having slots along the line 7--7 in FIG. 6 looking at the arrow.

FIG. 8 illustrates a perspective view of a portion of another embodimentof this invention in the form of a belt with projections and meanshaving slots.

FIG. 9 illustrates a side elevation view of the embodiment shown in FIG.8.

DESCRIPTION

Referring now to the drawings and in particular to FIGS. 1 and 2 a sideelevation view and a top plan view, respectively, of the preferredembodiment of the huller of my invention are shown. A frame 10 issupported by uprights 12, frame 10 supports a hopper 14 for dispensingunhulled pistachio nuts to be hulled between a drum 16 and a base 30having slots 31. The drum 16 has projections 18 disposed outwardly onthe peripheral surface 20 thereof. The peripheral surface 20 is normallymade of metal or other non-flexible material, however, a hard rubber orsimilar non-metal surface will suffice for the peripheral surface 20.Sweep 19 is attached to the peripheral surface 20 and extends the lengthof the cylinder 16 and is parallel to the axis 26 of the cylinder 16.Sweep 19 extends outwardly from the periphery 20 a short distance butdoes not extend as far as the pins 18.

The drum 16 is mounted on a shaft 22 extending through the center of thecylinder 16. The shaft 22 is journaled to frame 10 through suitablejournals 24a and 24b which journals support the driving shaft 22. Theshaft 22 is designed to rotate about a transverse horizontal axis 26.Attached to the upright 12 is an electric motor 50 and a driving belt 52which couples sprocket 54 attached to shaft 56 of the motor 50 and thesprocket 28 attached to the shaft 22. In operation the rotation of thedrum 16 is in the direction indicated by the arrow 58.

The hopper 14 is provided to receive the unhulled pistachio nuts and ismounted to frame 10. The hopper has an elongated shoot 15 and a gate 17which controls the passage of the unhulled nuts to be abraded betweenthe peripheral surface 20 of the cylinder 16 and the base 30. The means30 and its supporting structure for coupling the means 30 to frame 10 isshown in detail in FIGS. 4 and 5 and is described in particular therein.

The rotary drum 16 mounted above base 30 coacts with the semi-flexiblebase 30 to push the nuts along the slots 31 formed within the base 30.The base 30 consists of a series of parallel semi-elastic strips 32which are serrated on their upper surface 33 which contacts the hulls ofthe pistachio nuts. The pins 18 embedded in the surface 20 of the drum16 force the nuts along the channels 31 in ordered sequence to avoid thesimultaneous passage of nuts through adjacent slots 31. As the nuts passalong the surface 33 while the nuts are in the slots 31 they aredehulled by the compressive force generated between the drum 16 and thebase 30. The dehulled nuts and loose hulls are ejected from the base bythe drum pins 18 and sweep 19. Once ejected the product enters shoot 11and passes through the air separator 15. Air blowing past the screen 15aof air separator 15 causes the hulls to be blown out opening 15b whilethe pistachio nuts drop out opening 15c into the container 15d. The term"pistachio nuts" as used herein, means the nut of the pistachio treecomprising the shell containing an oblong edible seed.

Referring now to FIG. 3, a perspective view of the preferred embodimentof the present invention is shown without hopper 14, air separator 15 orshoot 11. In normal operation the distance of the surface 33 of strips32 from the peripheral surface 20 must be adjusted to a desired spacingso that the unhulled pistachio nuts contact peripheral surface 20 andthe surface 33, as the unhulled pistachio nuts of most commercialharvest runs vary in size. Also, that distance must be adjusted as thepins 18 extending outwardly and perpendicular to the peripheral surface20 of the drum 16 should extend into the slots 31 formed by the strips32 to push the pistachio nut passing between said surface 20 and saidsurface 33 when the drum 16 is rotated in the direction indicated byarrow 58. One end of strips 32 are coupled to bar 70 and the other endsthereof are supported by a wire mesh 39 which is coupled to a bracket 60through metal strips 40 as more fully described hereinbelow. Thisadjustment of distance between the periphery 20 and the surface of thestrips 32 is accomplished by the horizontal movement of bracket 60 andthe vertical movement of square bar 70.

Bracket 60 is held by a threaded clamp 61a and 61b through the adjustingscrews 63a and 63b, respectively, passing through clamps 61a and 61b.The screws 63a and 63b are secured by nuts 64 to the sides of U-brackets65a and 65b, which U-brackets are in turn attached to frame 10. Theturning of the screws 63a and 63b causes the threaded clamps 61a and61b, respectively, secured to the bracket 60 to move the bracket 60horizontally on frame 10. Thus through the horizontal movement ofbracket 60 of the surface 33 the strips 32 of the means 30 can bebrought closer to or moved farther away from the peripheral surface 20of the drum 16. Also, attached to the frame 10 are L-bracket 71a and 71bhaving rectangular slots 72a and 72b respectively therein. Brackets 71aand 71b have a flange 73a and 73b respectively which flanges areperpendicular to the frame 10. The ends of the bolts 74a and 74b passthrough the threaded holes of square bar 70 near the ends of square bar70 with bolts 74a and 74b resting on the flanges 73a and 73brespectively. The turning of the bolt 74a and 74b in the threaded holesof square bar 70 vertically raises or lowers the bar 70 within the slots72a and 72b to adjust the surface 33 of the strips 32 of the means 30closer or farther from the peripheral surface 20 of the drum 16. Thusmovement of the bracket 60 and the bar 70 will change the spacedrelationship of the surface 33 with the surface 20 of the drum 16.

In operation the hopper 14, not shown in FIG. 3, dispenses unhulled nutsbetween means 30, formed in part of strips 32 to provide slots 31, andthe surface 20 of the drum 16 with the drum disposed above and in closeproximity to surface 33. The unhulled pistachio nuts fall onto theserrated surface 33 of the strips 32 and then partially into the slots31 which slots are spaced apart at a distance smaller than the shell ofthe pistachio nuts to be dehulled, yet the slots 31 are wide enough forthe nuts to rest in the slots 31. The nuts, as they are pushed by pins18 when drum 16 is rotated in the direction of arrow 58, are abraded bycompressive contact between peripheral surface 20 and surface 33 as ismore particularly described hereinbelow. The sweep 19 on each rotationof the drum 16 cleans and sweeps the fragments of the ruptured hullsfrom between the surface 20 and the surface 33.

Referring now to FIGS. 4 and 5, a top perspective view and a bottom viewof the base 30 having slots 31 and its supporting structure,respectively, are shown. Base 30 consists of a series of parallelyielding strips 32 which are semi-flexible and have serrations on thesurface 33 thereof. The strips 32 are retained in parallel position bysemi-flexible backing strips 35 which extend across the bottom of thestrips 32 and are attached to the surface opposite to surface 33 ofstrips 32. These strips 32 are retained in parallel position by backstrips 35 and are separated from each other to form slots 31therebetween. The semi-elastic combination formed from strips 32 andback strips 35 has one end of strips 32 fastened between braces 36 and37 by bolts 38 extending through braces 36 and 37 and the bolts 38 alsopass through square bar 70. Also, attached to square bar 70 is one endof a rectangular screen mesh 39. Wire mesh 39 is formed in an arc toprovide a back support for the base 30, to support the other end ofstrips 32 and to assist in maintaining serrated surface 33 of the strips32 in close proximity to drum surface 20. The other end of the wire mesh39 is coupled to a first end of metal strips 40 by means of braces 41and 42. The second end of metal strips 40 are attached to bracket 60. Ihave found that the strips 32 and the strips 35 may be formed from apolyvinylchloride material. I have also found for the hulling ofpistachio nuts, a width of approximately one-fourth of an inch(approximately 63.5 millimeters) for the serrated surface 33 isparticularly effective when the strips 32 are formed in parallelrelationship to each other on five-eighths of an inch centers(approximately 1.53 centimeters centers) to provide slots 31 ofapproximately one-fourth inch in width (approximately 63.5 millimeters).

Now referring to FIG. 6, a side view of a drum 16 and fragmentary viewof base 30 is shown. In normal operation, as the drum 16 rotates in thedirection of the arrow 58 the pins 18 pass through the slots 31. Theunhulled nut, such as pistachio nut 13, being pushed by one of the pins18, not shown, is forced to pass between the surface 20 of the cylinder16 and the surface 33 of the strips 32 which strips are adjacentlyspaced in close proximity to each other at a distance narrower than thewidth of the nut 13. The rubbing and abrading action of the serratedsurface 33 and the drum surface 20 on the hull of the pistachio nut 13ruptures and the hull is stripped away from the nut 13. As the nut 13 isforced between the peripheral surface 20 and the yielding surfaces 33 ofadjacent yielding strips 32, both of which are in contact with the nut13 the strips 32 yield slightly and separate slightly to allow the nut13 to pass. The amount of yielding and separating of strips 32 isdependent upon the size of the pistachio nut. After the nut 13 haspassed any given position of the surfaces 33 that portion of strips 32then returns to their normal position. The pins 18 are spaced apart andstaggered on surface 20 in an ordered sequence to avoid the simultaneouspassage of nuts through adjacent slots 31. With this arrangement oncethe proper compressive force for dehulling is set between surface 33 andsurface 20 pistachio nuts of varying sizes can be dehulled without thenecessity for further adjustment to the various size pistachio nuts fromthe field run harvest.

Referring now to FIG. 7, a cross section of cylinder 16 and afragmentary section of means 30, along the line 7--7 is shown. Thefragmentary section of means 30, as shown consist of a portion of theflexible strip 32, a cross section of the flexible back strips 35, and aportion of support wire 39. In operation as the cylinder 16 is rotatedin the direction indicated by arrow 58 pin 18 pushes the nut 13, withthe hull 13a in contact with peripheral surface 20 and serrated surface33. These contacts with the hull 13a of the pistachio nut 13 rupture thehull 13a and abrades the hull 13a from the pistachio nut 13. Thefragments of hull 13a after the hull is abraded and removed from the nut13 either fall through the slots 31, not shown, or are ejected with thenut at the end of the strip 32 by the projection 18 or the sweep 19. Thewire mesh 35 in addition to providing support for the strip 32 as thenut 13 passes, between the peripheral surface 20 and the surface 33 ofthe strip 32 is so constructed to allow the fragments of hull 13a topass through the opening in the wire mesh 35.

Referring now to FIGS. 8 and 9, a portion of another embodiment of thepresent invention is illustrated wherein only the coacting elements thathull the pistachio nuts are shown. The other portions of this embodimentare conventional, are known in the art, or are discussed above inconjunction with the preferred embodiment.

Briefly, in this embodiment, trained around the drums 116a and 116b isan inner surface 108 of a belt 117. The belt 117 has an outer surface120 with outwardly extending projections 118 embedded in said surface120. The surface 120 is located above and in close proximity to surfaces133 of the strips 132 of base 130 having slots 131. The means 130 havingslots 131 consists of a series of parallel semi-elastic strips 132 whichstrips have serrated surfaces 133 which contact the nuts. The strips 132are retained in parallel position by back strips 135 and are separatedfrom each other to form slots 131 therebetween. The slots 131 are sospaced apart to be narrower than the width of the pistachio nut to behulled yet wide enough for said nut to rest in slot 131.

As the drums 116a and 116b are rotated in the direction of the arrows158 and 159, respectively, the pins 118 embedded in the surface 120force the nuts 13 through the channels 131 in an ordered sequence toavoid simultaneous passage of nuts through adjacent channels. As thenuts 13 pass through the channels 131 they are hulled by the compressiveforce generated between the surface 120 and the surface 133.

Tension device 180 is positioned below means 130 and in contact with themeans 130. The springs 181 of tension means 180 forces a member 182against means 130 to urge the strip 132 toward belt 117 to maintain acompressive force on the hulls of the nuts 13 passing between surface120 and serrated surface 133. The hulled nuts and the loose hulls areejected from the means 130 by the pins 118 or the clean sweep 119 whichis attached to surface 120. Once ejected the produce enters aconventional air separator, not shown, and the hulls are blown away fromthe nuts.

I claim:
 1. A method of removing hulls from pistachio nuts said methodcomprising the steps of(a) depositing unhulled pistachio nuts betweenrotating means having projections extending outward from a surfacethereof and a means having slots, said projections being spaced apart onsaid surface and said surface movably mounted on support means with saidsurface having projections disposed in close proximity to .[.the.]..Iadd.a .Iaddend.surface of said means having slots so that theprojections extend into the slots, said slots being narrower than thepistachio nuts; (b) passing said unhulled pistachio nuts between thesurface having projections and .[.a.]. .Iadd.the .Iaddend.surface ofsaid means having slots by means of moving the surface of said meanshaving projections, so as to push said pistachio nuts in said slots withsaid projections; and (c) abrading said hulls from said pistachio nutsby means of the surface having projections and the surface of said meanshaving slots contacting said hulls while said unhulled pistachio nutspass between said surface having projections and said surface of saidmeans having slots.
 2. A method of removing hulls from pistachio nutssaid method comprising the steps of:(a) depositing unhulled pistachionuts between rotating drum having projections extending outward from theperipheral surface of said drum and a means having slots, saidprojections being spaced apart on said surface and said surface movablymounted on support means with said surface having projections disposedin close proximity to .[.the.]. .Iadd.a .Iaddend.surface of said meanshaving slots so that the projections extend into the slots, said slotsbeing narrower than said pistachio nuts; (b) passing said unhulledpistachio nuts between said peripheral surface and .[.a.]. .Iadd.the.Iaddend.surface of said means having slots by means of rotating saiddrum, so as to push said pistachio nuts in said slots with saidprojections; and (c) abrading said hulls from said pistachio nuts bymeans of the surface having projections and the surface of said meanshaving slots contacting said hulls while said unhulled pistachio nutspass between said surface having projections and said surface of saidmeans having slots.
 3. A method of removing hulls from pistachio nutssaid method comprising the steps of:(a) depositing unhulled pistachionuts between a movable belt having projections extending outward from asurface thereof and a means having slots, said projections being spacedapart on said surface and said surface movably mounted on support meanswith said surface having projections disposed in close proximity to.[.the.]. .Iadd.a .Iaddend.surface of said means having slots so thatthe projections extend into the slots, said slots being narrower thansaid pistachio nuts; (b) passing said unhulled pistachio nuts betweensaid surface having projections extending therefrom and .[.a.]..Iadd.the .Iaddend.surface of said means having slots by means of movingsaid surface having projections so as to push said unhulled pistachionuts in said slots with said projections; and abrading said hulls fromsaid pistachio nuts by means of the surface having projections and thesurface of said means having slots contacting said hulls while saidunhulled pistachio nuts pass between said surface having projections andsaid surface of said means having slots.